PHILADELPHIA -- A former assistant professor at Arizona State University is facing criminal charges for allegedly threatening a treasured piece of American history.

According to authorities, Carlos Balsas, 41, of Tempe, was charged with making terroristic threats and several other offenses on Sunday after he said he was going to blow up Philadelphia’s Liberty Bell.

Balsas reportedly claimed to have explosives in his possession when he walked into the historic site.

Two black backpacks were found nearby and a bomb squad was brought in. No explosives were found, and the scene was eventually cleared.

According to Maricopa County Superior Court records, Balsas was an ASU assistant professor beginning in 2004, teaching urban planning. He was denied tenure and promotion to associate professor after a lengthy performance review process that began in 2009.

He filed a lawsuit against the university over that decision in 2012. The court ruled against him on Jan. 14.

Balsa reportedly has not worked at ASU since 2011.

ASU officials did not return a 3TV request for comment Sunday.

Balsas faces a host of federal charges including making terroristic threats. The U.S. Attorney’s Office is expected to review the case on Monday.

Editor's note: The headline of this story has been updated to reflect that the suspect, Carlos Balsas, was an assistant professor at Arizona State University, not a professor.